Sarcoid-like pattern in a patient with tuberculosis.

For several decades the “mystery” of sarcoidosis has continued to evade revelation. Nowadays, due to medical progress and the opportunity of performing highly specialized tests which assist the identification of this condition as a separate disease, the understanding of the eternal mystery appears closer. Nevertheless, many contemporary studies focus on the putative link between sarcoidosis and infectious antigens isolated from skin lesions. On the other hand, a golden rule to differentiate sarcoidosis from other conditions such as tuberculosis and sarcoid-like reactions is the sterility of granulomas. However, there are hypotheses which state that sarcoidosis could be related to tuberculosis and, in particular, to the Mycobacterium species. The similarities that many authors identify between the genetic signatures of the two conditions definitely raise concerns regarding: i) the inability to categorize every single case in a clear-cut way, namely in inflammatory/autoimmune or infectious; ii) the need of new criteria to clearly differentiate sarcoid-type reactions in the context of infectious diseases from sarcoidosis as an autonomous disease. We report the case of a 35-year-old male patient with histopathological evidence of sarcoid-like granulomas in cutaneous lesions on the face and imaging studies consistent with a systemic form of sarcoidosis. However, a positive QuantiFERON-TB Gold test and Ziehl-Neelsen staining was found, leading to the diagnosis of a rare case of TBC with histopathological evidence of sarcoid-like lesions. The following are also discussed: i) the potential role of tuberculosis antigens in the context of occult tuberculosis as generators of sarcoid-type of reaction; and ii) the necessity of additional diagnostic panels as a standard procedure in patients with suspected sarcoid granulomas of unknown origin.